many have added stack to their stoves. personally i see no harm in it..some say you can increase the draft with a long stack and that does make sense. if you think you have too much draft and are having boile over issues or you think your wood consumption is going up i can't see why you cant add a barometric "flapper" control that will allow you to set the draft to your liking.

what i was referring too is that some folks claim with a longer chimney they get more draft. when your stoves blower is not in operation (when your stove is at idle) the extra draft may pull air in around a door or through yoru blower when it normally wouldn't with a short chimney. if this were to happen you could get boileover. if you were to add the barometric flapper, that would control your draft. this draft control could keep your actual draft on the stove the same (or very close too) as it was when your chimney was shorter

Forced draft wood boiler owner here. Extended tall stack as well...Its like night and day compared to the factory stack (smoke wise)...No problems at all..Just run a hot fire here and there to keep your stack clean..Also spend the money and buy the good pipe.. If money is tight...Wood stove pipe works..But you'll be buying it every yr cause it rots.. Plus it plugs up since its not insulated..Been there done that lol.. How high you plan on going?

Forced draft wood boiler owner here. Extended tall stack as well...Its like night and day compared to the factory stack (smoke wise)...No problems at all..Just run a hot fire here and there to keep your stack clean..Also spend the money and buy the good pipe.. If money is tight...Wood stove pipe works..But you'll be buying it every yr cause it rots.. Plus it plugs up since its not insulated..Been there done that lol.. How high you plan on going?

It helps to put a larger pipe to put around it. Round duct would probably even work for the outside pipe and it pretty cheap. Cap the ends so there is trapped air between the pipes or use some type high temperature insulation between them.

I have 14' of metalbestos on mine and its force draft as well. This I my first year running it so I dont have anything to compare it to as far as running it with no chimney. I just throw in a pile of card board every once and a while to give it a cleaning its been running since the begining of oct no boilovers and we had some warm days during that span.

Mine has fan, I added 12ft to mine and have not had any problems. Used insulated kind tried stove pipe one year and thats all it lasted. I needed to get smoke up higher to. It does increase draft on stove or it did mine but has not been a problem.

Good input. Just what I was looking for. And thanks WillieG. I think I will measure the draft at an idle with a manometer and install a barometric damper so I can match the draft no matter the height. I was thinking about using a piece of 8 inch galvanized well casing about 15 feet tall or so. I could weld a base to it to bolt it to a concrete pad off to the side of the boiler and run some stainless duct to that. That will give me a place to put the barometric damper. Put a clean out at the bottom for a brush and I think I'll be ready to go.

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i used a pieceof 8 inch schedule 40 black pipe for my chimney but i work in the chemical plansts and was able to get 1200 degree insulation and the aluminum wrap they put over that you may not need the barometric flapper as it sounds like most guys doent need it, i only suggested it in case the extra chimney causes a draft through a door gasket or something that normall would not show up with the short stack

my chimney is welded right to my stove...my stove is schedule 80 pipe so it supports it. as well the box taht the chimney goes through on top of my building is made from 3/16 steel and it is bolted to 2 trusses, so it supports against any side ways motion